Area code 510 is in California, USA. It was put into service on September 2, 1991, and has been in use ever since. The area code overlays area codes 510 and 341.
California Counties within Area Code 510
Alameda and Contra Costa.
California Major Cities within Area Code 510
Alameda, Berkeley, Castro Valley, El Cerrito, Emeryville, Fremont, Hayward, Hercules, Newark, Oakland, Piedmont, Pinole, Richmond, San Leandro, San Lorenzo, San Pablo, and Union City.
Area Code 510 Time Zone?
510 is located in the Pacific time zone, which is known as America/Los Angeles.